we know that the faa has established a no-fly zone over watertown, massachusetts. amtrak has been suspended indefinitely from new york to boston. let's get to scott cohn. he's been in boston since the attacks. what's happening where you are, scott? >> i'm also in watertown, maria, and for much of the day, really for all of the day, we were on mt. auburn avenue, which is where the chase went down overnight. we've moved more for transmission issues than anything else, it's not that the situation has changed appreciably, but i've had a little different vantage point of the same things that bill was talking about. and it took us a while to figure out what was going on. but it seems pretty clear, they were just, as they said, they were going house to house. and it looked like they were sort of going sector to sector to sector. there would be an aerial reconnaissance above, sometimes there were military helicopters accompanying them as well. and then you would see lines of yu uniformed police officers and also s.w.a.t. officers going door to door, with guns, not necessar